Dictionaries are descriptive, not prescriptive. They describe how language is used and has has previously been used. They don't determine how it should be used.
There's no such thing as an "official" dictionary either (at least not in English).
Not a dictionary, but here's an "official" source that uses it (a text book).
Argumentation and Debate By Austin J. Freeley, David L. Steinberg, 13th edition 2013. Page 80:
"Taking evidence out of context, also referred to as quote mining, contextomy, suppressed evidence or cherry picking, my offer a convenient way to find the quotes and conclusions which will support a claim, or to avoid consideration of parts of the evidence which are counter to your conclusion, but it is intellectually dishonest and when brought to light likely to be a counterproductive strategy."
And? It's a neologism. That's hardly surprising. So are the words quark, cyberspace, internet, brunch, smog, chortle, nerd, laser, feminist, yuppie and yahoo.
New words get added to dictionaries all the time.